package org.example.utils;

import com.alibaba.fastjson.JSON;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.interfaces.Claim;
import com.auth0.jwt.interfaces.DecodedJWT;
import org.example.domain.UserToken;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

/**
 * @desc   使用token验证用户是否登录
 * @author zm
 **/
public class TokenUtils {
    //设置过期时间 30分钟
    private static final long EXPIRE_DATE=30*60*1000;
    //token秘钥
    private static final String TOKEN_SECRET = "ZCfasfhuaUUHufguGuwu2020BQWE";

    public static String generate (UserToken userToken){

        String token = "";
        try {
            //过期时间
            Date date = new Date(System.currentTimeMillis()+EXPIRE_DATE);
            //秘钥及加密算法
            Algorithm algorithm = Algorithm.HMAC256(TOKEN_SECRET);
            //设置头部信息
            Map<String,Object> header = new HashMap<>();
            header.put("typ","JWT");
            header.put("alg","HS256");
            //携带username，password信息，生成签名
            token = JWT.create()
                    .withHeader(header)
                    .withClaim("userToken", JSON.toJSONString(userToken))
                    .withExpiresAt(date)
                    .sign(algorithm);
        }catch (Exception e){
//            e.printStackTrace();
            return  null;
        }
        return token;
    }

    public static boolean verify(String token){
        /**
         * @desc   验证token，通过返回true
         * @params [token]需要校验的串
         **/
        try {
            Algorithm algorithm = Algorithm.HMAC256(TOKEN_SECRET);
            JWTVerifier verifier = JWT.require(algorithm).build();
            DecodedJWT jwt = verifier.verify(token);

//            Claim username = jwt.getClaim("username");
//            System.out.println(username.asString());

            return true;
        }catch (Exception e){
//            e.printStackTrace();
            return  false;
        }
    }

    public static UserToken getUserToken(String token){
        try{
            DecodedJWT jwt = JWT.decode(token);
            return JSON.parseObject(jwt.getClaim("userToken").asString(),UserToken.class);
        }catch (JWTDecodeException e){
            return null;
        }
    }

    public static void main(String[] args) {
        UserToken userToken = new UserToken();
        userToken.setUserId(1);
        userToken.setUsername("zhangsan");

        String token = generate(userToken);
        System.out.println(token);


        boolean b = verify(token);
        System.out.println(b);
        System.out.println(getUserToken(token));

    }
}